:root {
  --bg-deep:    #080f1a;
  --bg-mid:     #0d1827;
  --bg-card:    #112035;
  --accent:     #4fc3f7;
  --accent-dim: #1e6b8c;
  --btn-bg:     #b2ebf2;
  --btn-text:   #080f1a;
  --text-main:  #e8f4fd;
  --text-muted: #a3c7e6;
  --border:     rgba(79, 195, 247, 0.15);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--bg-deep);
  color: var(--text-main);
  font-family: 'Switzer', sans-serif;
  font-weight: 400;
  line-height: 1.6;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
  opacity: 0.35;
}

section {
  position: relative;
  z-index: 1;
}

nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 48px;
  background: rgba(8, 15, 26, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.logo {
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--text-main);
  text-decoration: none;
}

.nav-right {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-link {
  color: var(--text-main);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s;
}
.nav-link:hover { color: var(--accent); }

.btn-primary {
  display: inline-block;
  background: var(--btn-bg);
  color: var(--btn-text);
  font-family: 'Switzer', sans-serif;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 10px 26px;
  border-radius: 50px;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.2s, box-shadow 0.2s;
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(79, 195, 247, 0.3);
}

.hero-btn {
  font-size: 1.15rem;
  padding: 16px 48px;
  border-radius: 14px;
  animation: pulse-glow 3s ease-in-out infinite;
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: 0 0 0 0 rgba(178, 235, 242, 0); }
  50%       { box-shadow: 0 0 32px 8px rgba(79, 195, 247, 0.25); }
}

#hero {
  text-align: center;
  padding: 100px 24px 80px;
  background: radial-gradient(ellipse 70% 50% at 50% 0%, rgba(79, 195, 247, 0.12) 0%, transparent 70%);
}

#hero h1 {
  font-size: clamp(2.4rem, 6vw, 3.8rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  max-width: 680px;
  margin: 0 auto 24px;
}

#hero h1 span {
  color: var(--accent);
}

#hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 480px;
  margin: 0 auto 40px;
}

#pain {
  background: var(--bg-mid);
  padding: 80px 24px;
  text-align: center;
}

#pain h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 800;
  margin-bottom: 48px;
}

.pain-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  grid-auto-rows: 1fr;
  gap: 16px;
  max-width: 720px;
  margin: 0 auto;
  list-style: none;
}

.pain-card {
  display: flex;
  align-items: center;
  justify-content: center;
  background: #012A4A;
  border: 1px solid rgba(79, 195, 247, 0.25);
  border-radius: 12px;
  padding: 20px 24px;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-main);
  text-align: center;
  transition: transform 0.2s;
}
.pain-card:hover {
  transform: translateY(-3px);
}

#how {
  padding: 80px 24px;
  text-align: center;
}

#how h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 800;
  margin-bottom: 48px;
}

.how-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  max-width: 760px;
  margin: 0 auto;
  align-items: center;
}

.puzzle-img {
  width: 100%;
  border-radius: 16px;
  overflow: hidden;
  aspect-ratio: 4 / 3;
  background: var(--bg-card);
}

.puzzle-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  border-radius: 16px;
}

.steps-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  list-style: none;
}

.step-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px 16px;
  text-align: center;
  transition: border-color 0.2s, transform 0.2s;
}
.step-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}

.step-num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 10px;
}

.step-label {
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 500;
}

#level {
  background: var(--bg-mid);
  padding: 80px 24px;
  text-align: center;
}

#level h2 {
  font-size: clamp(1.6rem, 4vw, 2.2rem);
  font-weight: 800;
  margin-bottom: 16px;
}

#level > p {
  color: var(--text-muted);
  max-width: 520px;
  margin: 0 auto 40px;
  font-size: 0.98rem;
}

.level-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  max-width: 500px;
  margin: 0 auto;
  padding: 28px 32px;
}

.level-label {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 14px;
  font-weight: 500;
}

.level-bar-track {
  background: rgba(255, 255, 255, 0.08);
  border-radius: 99px;
  height: 10px;
  overflow: hidden;
}

.level-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  border-radius: 99px;
  transition: width 1.8s cubic-bezier(0.16, 1, 0.3, 1);
}

.cefr-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 10px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

#cta {
  padding: 100px 24px;
  text-align: center;
  background: radial-gradient(ellipse 60% 60% at 50% 100%, rgba(79, 195, 247, 0.1) 0%, transparent 70%);
}

#cta h2 {
  font-size: clamp(1.8rem, 5vw, 3rem);
  font-weight: 800;
  margin: 0 auto 36px;
  max-width: 600px;
}

footer {
  border-top: 1px solid var(--border);
  padding: 28px 48px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 12px;
}

footer nav {
  position: static;
  background: none;
  border: none;
  backdrop-filter: none;
  padding: 0;
  display: flex;
  gap: 24px;
}

footer a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s;
}
footer a:hover { color: var(--accent); }

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 640px) {
  nav {
    padding: 14px 20px;
  }
  .how-inner {
    grid-template-columns: 1fr;
  }
  .puzzle-img {
    display: none;
  }
  footer {
    flex-direction: column;
    text-align: center;
    padding: 24px 20px;
  }
  footer nav {
    justify-content: center;
  }
}